Concentric conducting system



July 12, 1932- H. A. AFFEL CONCENTRIC CONDUCTING SYSTE.

Filed nay 23, 1929 ATTORNEY Patented uly .12, 1932 UNITED STATES PAT-ENT omer, A'

HERMAN A. AFFEL, 0F RIDGEWOOD, NEW JERSEY, -ASSIGNOR T0 AMERICAN TELI- IHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK CONCENTRIC CNDUCTING SYSTEM Thisiinvention relates to a novel form of conduct-or structure employing concentric cylindrical conductors for the transmission of a wide band of frequencies with relatively low attenuation, and has more particularly to dowith the maintenance of such a system in proper operating condition.

If a hollow cylindrical conductor is provided with a return conductor comprising a second hollow cylindrical conductor concentrically arranged with respect to the first conductor, and the two conductors are separated by a dielectric consistingr largely of air or other gaseous medium, the 1transmission line thus formed will have a number of desirable characteristics. Its attenuation at all frequencies will be quite low as compared with the corresponding attenuation of open Wirelines and cable circuits such as are now commonly used for telephone transmission. Such a transmission circuit may, therefore, be employed for the transmission of a much wider band of frequencies thanI has been possible with types of transmission circuits heretofore used. It also has the advantage that it is substantially free from interference from neighboring conductor systems and in itself tends to produce but little interference into adjacent transmission circuits.

In such a system the two conductors are usually maintained in proper concentric relation to each other by dielectric spacers or washers interposed between the two conductors. It is highly essential for the proper operation of the system that these spacing washers be maintained dry and clean. If the outer conductor be a copperpipe or even be made up of stranded wire braided or woven in the form of a hollow cylinder and. covered with waterproofing material, the conducting system will be maintained dry and increased leakage losses due to the improper functioning of the dielectric spacers will be avoided. If, however, the outer conductor should be vpunctured, either duc to an accident or to deterioration, moisture would be enabled to env ter the space between the two concentric conductors and might result in putting the system out of commission. ln order to avoid thls effect it is proposed, in accordance with the a circulation of air vor gas under' pressure,

any opening in the outer conductor which might enable moisture to enter would be indicated by a drop in pressure, so that the trouble could be at once located and corrected. If any considerable amount of water should enter the system, the water may be drained off by means of drain cocks or by means of suitable pumps, and the remaining moisture in the air may be removed by passing the air which circulates in the system through' a suitable air cleaning and drying apparatus.

The invention will now be more fully un derstood from the followin description when readv in connection wit the accompanying drawing, the ligure of which shows a preferred arrangement of the invention.

Referring to the drawing, a concentric conductor transmission system is schematically indicated ascomprising an outer tubular conductor 10, with an inner tubular conductor 12 arranged on the interior thereof and concentrically therewith. The two conductors are maintained in proper spaced relation by means of washers such as 14 spaced at suitable intervals, and preferably these washers have transverse openings through them to 'permit of the circulation of air inthe space Pires and clean condition, as any dirt or moisture permits the transmission between the two concentric conductors of leakage currents. So long as the outer conductor is maintained waterproof, this condition will obtain, but i the outer cylindrical conductor be punctured, either by accident or due to deterioration by en osure to the elements, moisture be ena led to enter the space between the two conductors.

` In order to overcome this diculty, the inner cylinder or pipe 12 is connected at one end through a section of pipe 16 to the outer pipe or tu e l0. In order to prevent shortcircuiting the terminal electrical apparatus at A, the pipe i6 should include an insnlatn ing section or be otherwise constructed so that conduction cannot take place between the two conductors il@ and l2 thi-ouch the pipe 16. A suitable blower or pump y is provided at the other end of thesystem, and the output oi the blower is connected by means of a pipe 18 through an air cleaner and dehydrater schematically indicated at C to the interior of the outer pipe or conducting tube 10. The inner' conducting tube or pi e 12 is connected through a ipe 20 to the input side of the blower or ivan B. It is, of course, necessary that en insulating section be included in the 18 or 20, or both, to prevent short-circuiting of theelectricalapparatus at A. A

t hea' manometer M for indicating pressure may be associated with the pipe 18, and a psychrometer P oi: known type for indicating the humidity or amount of moisture in the circulating airma be associated with the return pipe 20. If esired, heating or ycooling apparatus H may also be included in the pipe 20 where it is desired to maintain the circulatin air at a predetermined temperature. The lower B, cleaner and dehydrater C, or cooling apparatus H, manometer M an psychrometer P may all be of any hown t andare merely indicated sche matically in the drawing. c

Whenthe blower B is operated the air will i be forced under pressure through the space between the outer conductor 10 and the inner conductor 12, and will be returnedthrough the pipe 16 to the inner conductor 12 and thence through the pipe 20 to the blower. The :nanometer M will indicate the pressure of the circulating air and if a leak should occur in the outer conductor 10 this fact will be indicated by a decrease of the pressure indication upon the part of the manometer M.

If, during the normal operation, any moisture should enter the space between the two conductors, this fact will be indicated by the peychrometer P. The air cleaner and dehydraterC will, of course, Yfunction to remove the moisture from the circulating air and the interior of the conductor 10 will, therefore, be maintained in a dry condition .S0 that leakage across the insulating spacers 1Q will be maintained at a minimum.

If the outer conductor 10 should be punctured so that any considerableamount of wathrough the system by speeding up the blower B, the transmission circuit may be maintained suliciently dry for transmission purposes pending the location and repair of the leak. Even where the system has been put entirely out of commission, until the leali has been located and repaired the drain cocks 24 are useful in draining off the water, and the air circulating system is then put into op eration to dry out the system so that it can be again used. ,A

It will be obvious that the'general principles herein disclosed maybe embodied in many other organizations widely different from those illustrated without departin from the spirit of the invention as define in the following claims.

What is claimed is:

1. In a concentric conductor system comprising concentrically arranged tubular conductors for electricit a gas conduit connecting one end of t e-innertubular conductor to the space between the conductors for the flow of gas between said inner conductor and said space, and gas pumping means having an input connection and an output connection, one of said connections being associated with the other end of said inner tubular conductor and the other connection being connected to the space betweensaid conductors, whereby a continuous ilow of gas is maintained through the space between said conductors and through the inside ofthe inner conductor in tandem.

2. In a'concentric conductor system comprising concentrically arranged tubular conductors for electricity, a gas conduit connecting one endl of the inner tubular conductor to the space between the conductors for the flow of gas between said inner conductor and said space, gas pumping means having an input connection and an output connection, one

of said connections being associated'with the other end of said inner tubular conductor and the other connection being connected to the space between said conductors, whereby a continuous {lowof gas is maintained through the spacel between said conductors and through the inside of the inner conductor in tandem, and means to indicate the p in the system.

3. In a concentric conductor system com prising concentrically arranged tubular conductors for electricity, angas conduit connecting one end of the inner tubular conductor to the space between the conductors for the 110W of gas between said -inner conductor and 130 said space, gas pumping means having an in put connection and an output connection, one of said connections being associated with the other end of said inner tubular conductor and the other connection being connected to the space between said conductors, where'v by a continuous ow of gas is\ maintained through the sEace between said conductors and through t e inside of the inner conductor in tandem, .and means to indicate the moisture in the gas returning to the pumping means after circulation.

4. In a concentric conductor system com'- prising concentrically arran d tubular conductors for' electricity, a gas conduit connecting one end of the 1nner tubular conductor to the space between the conductors for the ow of gas between said inner conductor and said space, gas pumping means having an input connection and an output connection, one of said connections being associated with the other end of said inner tubular conductor and the other connection being connected to the space between said conductors, whereby a continuous flow of gas is maintained through the space between said conductors and through the inside of the inner conductor in tandem, and means to remove the moisture from the gas returning to said pumping means after circulation. n

In testimony whereof, I` have signed my name to this specification this 20th day of May, 1929.' L

HERMAN A. AFFEL. 

